When a decision goes awry, we tend to focus on the people who made it, rather than on the decision itself. Our assumption, which is really unwarranted, is that good people make good decisions, and vice versa.

Good decisions don't always have a good outcome, just as bad decisions don't always have bad outcomes.

For example, if you are sitting at a blackjack table and happen to receive an 18 on the first two cards, should you hit when the dealer asks as a courtesy? Let's suppose you take that hit and the next card is a 3. You made a horrible decision but you lucked out. Worse, you might never know that you made a poor decision.

We can look at this in a simple two-by-two matrix.

In talking about this matrix, Paul DeDodesta, the Harvard stats wiz featured in Moneyball, writes:

We all want to be in the upper left box – deserved success resulting from a good process. … The box in the upper right, however, is the tough reality we all face in industries that are dominated by uncertainty. A good process can lead to a bad outcome in the real world. In fact, it happens all the time.

… As tough as a good process/bad outcome combination is, nothing compares to the bottom left: bad process/good outcome. This is the wolf in sheep's clothing that allows for one-time success but almost always cripples any chance of sustained success.

This is where it gets interesting.

If you can't recognize when you've had ‘dumb luck,' you'll never be in a position to correct the way you're making decisions. Eventually your luck runs out.

A group of managers of identical (moderate) ability will show considerable variation in their performance records in the short run. Some will be found at one end of the distribution and will be viewed as outstanding; others will be at the other end and will be viewed as ineffective. The longer a manager stays in a job, the less the probable difference between the observed record of performance and actual ability. Time on the job increased the expected sample of observations, reduced expected sampling error, and thus reduced the chance that the manager (of moderate ability) will either be promoted or exit.

Luckily we can improve our ability to make better decisions:

Maybe executives in responsible positions should be required to keep logs, as sea captains do. After each decision, a manager would list his or her reasons for having made it and record how it turned out.

… Usually the only information we have about how and why decisions were made is in the self-serving memoirs of great managers, which leave us feeling that some people just have it and other don't. But what is “it?” We have very little vocabulary for talking about internal thought processes. Decisions feel as if they jump fully grown from one's head.

A good decision is known before the outcome. It involves a mental representation of the facts known at the time as well as applied judgment. Good decisions are valuable but they are more valuable if they are part of a good decision process because a good process allows for feedback about where you can improve. This feedback, in turn, allows you to constantly get better at making decisions.